Surface Edit Points

[encephalon]

here a topic discussing this slightly

Edit/Greville point explanation wanted

Anyone know of a reference describing Greville points and why they are useful for editing curves? I’m curious why Greville points are used in Rhino as edit points. For non-uniform knot spacing the Greville points do not coincide with knots. (I.e. the points on the curve with the knot parameter values for those who prefer to consider knots as only parameter values.)